Generally, an electrostatic levitation furnace comprises, in an enclosed space evacuatable in a vacuum, a pair of electrodes and an optical system irradiating a sample levitated between electrodes with a laser beam which is condensed at the outside of the enclosed space and led into the inside thereof, and the furnace makes a vacuum in an enclosed space, levitates a charged sample by an electric field generated between electrodes, and irradiates the sample with a laser beam to subject to heat treatment without contact.
In order to effectuate the better heat treatment of a sample, it is preferable that this kind of electrostatic levitation furnace is used under weightless environment including microgravity conditions. As the ways of generating weightless environment are that of mounting an electrostatic levitation furnace on a space craft or an aircraft and that of using a drop tower which subjects the furnace to free fall.
However, when employing an aircraft, which is one of the ways of generating weightless environment for an electrostatic levitation furnace, the gravity level of the furnace is the order of 10−2G, which is not necessarily adequate for the weightless environment thereof. When employing a space craft or a drop tower, the gravity level of the furnace is the order of 10−3G, which is adequate for the weightless environment thereof than using the aircraft, but then, such cases have some problems that the apparatus becomes large scale and requires enormous amounts of cost and to conduct a multitude of experiments with changing parameters has difficulty.